The 2002 autopsy of former pro football player Mike Webster changed Dr. Bennett Omalu’s life. But the disease he discovered inside the 50-year-old’s brain -- which he named Chronic Traumatic Encephalopathy -- has sparked a revolution.

A growing awareness of CTE has started to change how doctors diagnose and treat brain injuries in patients of all ages. More and more evidence shows the long-term damage caused by repeated blows to the head, and this knowledge has begun to shape how athletes at all levels protect their skulls. It has even affected how the public feels about the violent sports that are so deeply rooted in our American culture.